1. Technical Field
The invention concerns a ship comprising at least one motor for driving the ship and at least one crane.
2. Description of the Related Art
The drive for ships by means of engines or electric motors is known in many various forms. In that respect cargo ships generally use diesel assemblies of large volume. In smaller ships or also sailing ships electric motors are in part also known as the drive for same. So-called diesel-electric drives are also known, in which an electric motor serves as a drive but the electrical energy for operation of the electric motor is converted by means of diesel assemblies.
Such a drive by means of electric motors is disclosed for example in DE 10 2008 018 420 A1. That document discloses a drive device for a ship having a drive shaft for driving a propulsion unit of the ship in the form of a screw and a first and a second electric motor for driving the propulsion unit. The two motors are arranged in succession on the drive shaft, wherein the current converter for feeding electric current to the motors is disposed in the housing of the first motor. Thus one motor can be specifically designed for travel within a port while the second motor is optimized for high-speed travel.
If one of the motors fails the ship can continue to be moved with the second motor. It is sub-optimum for travel in the borderline case to have to be continued with a motor which is not optimized for that travel mode.
A further problem involves maintenance and repair of such motors. They are usually maintained and repaired on board the ship, for the drive of which they are designed. That means that the ship must remain in a port and cannot be used over the entire period of maintenance or repair. That causes high cost levels, particularly in the case of cargo ships, as not only does that involve the maintenance and repair costs as well as the berthing costs in the port, but also the costs which arise due to non-use of the ship are to be taken into account. Maintenance or repair is made more difficult by virtue of the fact that the space around the motors is generally very constricted. The lighting conditions in a ship's engine room are also not optimum.
If major repairs are to be performed on the ship motors they are also partially exchanged. For that purpose the motors generally have to be dismantled and removed from the ship. That is a highly time- and cost-intensive activity.